Existing oscillators usually have process compensation, but without temperature compensation generally, so the frequency of the oscillators will vary with the temperature in practice, which is so-called temperature drift, to result in a lower precision of the outputted clock. Since the process compensation and the temperature compensation are restricted with each other, thus it's hard for the existing oscillators to design the process compensation and the temperature compensation separately, thereby the existing oscillators are hard to adjust and unable to meet a need for both the process compensation and the temperature compensation.
Therefore, it is necessary to provide an improved high-precision oscillator to overcome above drawbacks.